Cameron Mitchell

Resistance exercise training (RET) is potent stimulus to induce muscle growth. Heavier loads are traditionally more effective compared to lighter loads for inducing muscle growth, but recent research has demonstrated that lighter load (LL) RET can lead to similar muscle hypertrophy as higher load (HL) RET when training to volitional fatigue. While these results have been consistently shown in males, there is limited research on this topic using female participants. The aim of this study was to compare the muscle hypertrophic response to HL and LL RET in the upper and lower body of young adult females. It was hypothesized that there would be an equivalent increase between the HL and LL RET in both the upper and lower body. A randomized repeated measures within-participant design was utilized where each participant had one arm and leg assigned to train with HL and the other limbs assigned to train with LL. Participants trained thrice weekly for 10-weeks, performing unilateral knee extension and unilateral dumbbell bicep preacher curls. Biceps brachii thickness increased following both LL and HL RET (∆LL = 0.3±0.4 cm, ∆HL = 0.2±0.4 cm, Interaction P = 0.12), but upper arm lean mass only increased following LL RET (∆LL = 0.1±0.2 kg, ∆HL = 0.04±0.2 kg, Interaction P = 0.02). Neither HL nor LL RET induced an increase in any measure of lower body muscle size. LL RET induced a greater training volume compared to HL RET in the arms due to similar absolute loads used during training. In the lower body, training volume must be considered as neither loading condition reached the necessary total training volume required to induce measurable muscle growth.

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Background: It is estimated that 70% of individuals who undergo a massive weight loss (MWL) develop excess skin (ES). The ES around the abdominal area has been shown through patient reported outcome measures to negatively impact perceptions of physical function. Yet no studies have examined the impact of abdominal body contouring surgeries on direct measures of physical function.Study Objectives: The primary objective of this pilot study was to determine the variability of outcome measures in the context of ceiling, floor and learning effects to allow measuring the test-retest reliability of the physical performance measures. The secondary objectives of this study were to measure recruitment/retention, participant’s acceptability, and adherence to the protocol. The tertiary objective of this study was to provide data to estimate the effect size and sample size required to design a definitive non-randomized controlled trial.Materials and Methods: Patients who have undergone MWL were recruited through 4 medical clinics and were placed in either body contouring intervention group if they self-selected to undergo surgery or post massive weight loss matched control group. They participated in a series of physical function batteries of tests including 9-item modified physical performance test, 30s-chair to stand, star excursion balance test, timed up and go, modified agility t-test, 6-minute walk test, and body composition measures of fat mass and bone free fat free mass. There was a total of two visits which were 8-12 weeks apart to accommodate for recovery time for abdominal contouring procedures.Conclusion: It was found that tests involving dynamic balance, agility, and walking were reliable and showed medium to large effect size to be considered for future studies. Retention (72%) and recruitment (46%) rates were found to be compromised due to Covid-19 pandemic local limitations, and institutional surgical regulations. Depending on the primary outcomes of future trials, it is estimated that between 12 to 37 participants are required to be included in the sample size to achieve adequate statistical power.

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